Ultra-long interest-free deals on credit cards pose a risk to the economy by encouraging consumers to binge on debt, top bankers said yesterday.

Royal Bank of Scotland boss Ross McEwan and TSB chief executive Paul Pester spoke out against the deals amid concern Britain is facing a borrowing time bomb.

Credit-card debt is now rising at its fastest rate for 11 years and experts believe interest-free offers are part of the problem, persuading consumers to rack up debt without thinking about the consequences.

Royal Bank of Scotland boss Ross McEwan (left) and TSB chief executive Paul Pester (right) spoke out against the deals amid concern Britain is facing a borrowing time bomb

At present, Halifax and the AA both offer 30 months at zero interest. For balance transfers, where customers move their debt from one card to another, some firms offer a 43-month grace period.

Mr McEwan warned it led customers to delay paying back debt, the FT reported. He said: ‘Call me old fashioned, but I want customers to pay us back.’ He also warned many cards came with hidden fees, meaning spenders had no idea what the true costs were.

Credit-card debt is now rising at its fastest rate for 11 years and experts believe interest-free offers are part of the problem

Mr Pester said: ‘There are parts of the market we’re worried about, particularly these long low-interest balance transfer cards. They can’t be healthy – how can customers know in three or four years’ time if they’re able to afford them?’

Shoppers put £562million on credit cards in February – £20million a day.